Subject(s)
Education, Dental , Clinical Competence , Curriculum , Humans , Netherlands , Students, DentalABSTRACT
The degradation of luting cements was quantified when these cements were held as a 20-micron cement layer. The degradation process, which is mostly a sequence of absorption, disintegration, and solution, was expressed by a time-constant (tau). By using the same test specimens in vitro as well as in vivo, we determined the correlation of both situations.
Subject(s)
Dental Cements , Aged , Chemical Phenomena , Chemistry, Physical , Humans , In Vitro Techniques , Lactates , Middle Aged , Saliva/microbiology , Saliva/physiology , Solubility , Streptococcus mutans/physiologyABSTRACT
The described method of measuring degradation of luting cements in vitro, by which various media, including bacteriological, can be used, gives results indicating that degradation is a more complex process than could previously be measured. Degradation appears to be a process following a sequence of absorption, disintegration, and solution. Factors, such as cement, thickness of the cement layer, molarity, and pH of the medium, affect, mostly by interaction, the degradation speed. Though the clinical predictability of this test method is not yet determined, it gives the opportunity to measure the various stages of degradation and to appoint the different factors affecting this process. Clinical tests based on the same principle are in progress.
Subject(s)
Dental Cements , Chemical Phenomena , Chemistry, Physical , Glass Ionomer Cements , Hydrogen-Ion Concentration , Polycarboxylate Cement , Solubility , Time Factors , Zinc Oxide-Eugenol Cement , Zinc Phosphate CementABSTRACT
An analysis of the data yielded the following conclusions: 1. The use of a gelatin capsule in a metal casing combines the advantages of mechanical mixing and those of a disposable system. 2. In comparison to conventional mixing by hand, equal results can be obtained with mechanical mixing. 3. Mixing time and the use of a glass pestle will influence the setting time and the film thickness, whereas the type of casing only affects the setting time. No clear correlation was found between the temperature rise during mixing and the setting time, but the total quantity of the mix can influence the setting time. 4. The compressive strength was barely affected by the various mixing conditions.
